Electron-discharge device



Sept. 8, 1925. 1,552,606

' G. HOLST ET AL ELECTRON DI S CHARGE DEVI CE Filed Nov. 4; 1921 Patented Sept. 8, 1925.

UNITED STATES PATENT OFFICE.

GILLES HOIIST AND EKKO OOSTERHUIS, O'F EINDHOVEN, NETHERLANDS, ASSIGNOBS TO NAAMLOOZE VENNOOT'SGHA]? PHILIPS GLOEILAMPEN-FABRIEKEN, OF EIND- HO'VEN, NETHERLANDS.

ELECTRON-DISCHARGE DEVICE.

Application filed November 4, 1921. Serial No. 512,889. i

To all whom it may concern:

Be it known that we, GILLES HOLST and EKKo Oos'rnnnors, subjects of the Queen of the Netherlands, residing at Eindhoven, in the Province of North-Brabant, in the Kingdom ofthe Netherlands, have invented certain new and useful Improvements in an Electron-Discharge Device, of which the following is a ecification.

The inventlon relates to an improvement on the present type of gas-filled electron discharge devices and more particularly it relates to electron discharge devices comprising an incandescent cathode, an anode, a-

grid, and a filling of gas, such as are used in wireless telegraphy or telephony, and' which are generally known as soft valves. The object of the invention is to prov de a gas-filled electron discharge devicewhich may comprise a glass vessel .contalmng an incandescent cathode, an anode and a gr d interposed between the anode and the cathode and with a gas-filling of such nature and pressure that the device operates with reduced anode tension and is practically constant in its operation.

Attention has been drawn in technical literature to the fact, that gas-filled ionic valves show some advantages above ionic valves having a high vacuum. The most important advantage is the low' tension at the anode, necessary for a maximum strength of signal and the fact that when using gas-filled ionic. valves, a grid leak between the grid electrode and the incandescent filament becomes superfluous.

An inconvenience which occurs with asfilled valves is their lack of uniform action, which is due to the alteration of pressure of the gas-filling in consequence of the disappearance of gases and the emanation of new gases during the-operation of the valve.

The im rovement according to this invention conslsts in the glass bulb of the valve being exclusively filled with pure argon of low pressure.- By a preliminaryheatlng of the valve the glass and metal parts therein are freed from the greater part of the absorbed-gases.

.trated on which the invention may be incorporated.

As shown in the drawing the device comprises a receptacle 5 having enclosed therein a filament or cathode 1, an anode 3 and a grid 2, whereas the necessary contacts may he closed by means of the metal-fitting 5.

The inner space 6 of the receptacle is carefully evacuated, suitable steps being performed to expel all gases from the glass and from the electrodes e. g. by heating them up to a suitable temperature. The receptacle 5 is thus first evacuated as it were to have a permanent high vacuum, and the method described in the British Patent No. 15,788, A. vD. 1914, may be-adopted to accomplis this purpose.

After this the space 6 is exclusively filled with pure argon of a pressure not exceeding the upper-limit of mm. of mercury.

A thus treated device operates at an anode tension of 25-30 volts whereas in the heretofore employed high, vacuum tubes said tension amounts to 35100 volts.

In practice we have found that a very constant operation is obtained with a pressure of the argon of about mm. mercury; however a good result may also be obtained with slightly different pressures of the argon, as the proper pressure slightly varies plied, many changes may be made in the structure of the apparatus, Without departing from the scope of our invention.

What We claim is:-

1. An electric discharge tube comprising an'incandescent cathode, an anode, and a grid, and a gass' filling consisting, exclusively of pure argon of a pressure not ex ceeding mm. of mercury.

tures.

GILLES HOLST. EKKO OOSTERHUIS. 

